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Error code reference

LG Refrigerator Error Code Er FS

Abnormal Freezer Sensor

LG codesLG refrigerator codes

Abnormal Freezer Sensor - wire open, short circuit, temperature sensor damaged, or Main PCB damaged.

First step from the service manual

Check for loose connections on Main PCB, damage on wires, and resistance value of freezer thermistor at CON7 (blue to blue wires).

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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  • Wiring diagram references and connector pinouts from the OEM service manual
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What Er FS means on a LG refrigerator

Er FS is a freezer sensor fault code. The control board monitors resistance values from the freezer temperature sensor (thermistor) on a continuous basis. When the board detects resistance that falls outside the expected range due to either a short circuit or an open circuit (disconnection) in the sensor or its wiring, it sets the Er FS code and may alter or disable normal cooling operation to prevent damage.

For homeowners: your refrigerator has a small temperature-sensing component inside the freezer compartment that tells the control board how cold the freezer actually is. If this sensor loses its connection to the board, or if the wiring shorts out, the board can no longer read accurate freezer temperatures. The refrigerator does not know whether to run the compressor or not, which can lead to food spoilage if left unaddressed.

The fault is most often traced to a loose or disconnected wiring harness connector at the freezer sensor rather than a failed sensor itself. Inspecting and reseating the connector is always the first step before replacing any parts. If the wiring checks out, the thermistor itself should be tested with a multimeter for correct resistance values at a known temperature.

Source: manufacturer service documentation.

Common causes of Er FS

  1. 01

    Disconnected freezer sensor wiring harness

    Wiring / connection

    The connector linking the freezer thermistor to the wiring harness can loosen over time, especially after a defrost cycle or any service work. A disconnected connector creates an open circuit that immediately triggers Er FS.

  2. 02

    Damaged or shorted freezer sensor wiring

    Part replacement

    Wiring routed through the freezer compartment can be pinched, chafed, or damaged by ice buildup, causing a short circuit in the sensor circuit. A shorted wire will read out-of-range resistance and trigger the error.

  3. 03

    Failed freezer temperature sensor (thermistor)

    Part replacement

    The freezer thermistor itself can fail internally, producing either no resistance or an out-of-range resistance value even when the wiring is intact. Confirm this with a multimeter resistance test before replacing.

  4. 04

    Faulty main control board

    Part replacement

    If the sensor and all wiring test correctly, a damaged input circuit on the main control board can falsely report a sensor fault. This is the least likely cause and should only be considered after the sensor and wiring are confirmed good.

See the test procedure for each cause

Frequently asked questions about Er FS

What does Er FS mean on an LG refrigerator?
Er FS indicates the control board has detected a problem with the freezer temperature sensor, specifically a short circuit or a disconnection in the sensor or its wiring. The board cannot read a valid temperature from the freezer thermistor and displays this code to alert you to the fault. The freezer may not cool correctly while this code is active.
How do I fix Er FS on an LG refrigerator?
Start by unplugging the refrigerator, locating the freezer sensor wiring harness connector, and checking that it is fully seated. Reseating a loose connector often clears the code. If the connector is secure, inspect the wiring for visible damage or pinching. If the wiring looks intact, test the thermistor resistance with a multimeter and compare it to LG's specified values for that sensor at a known temperature. A thermistor that reads open or shorted needs to be replaced.
Can I still use my LG refrigerator when it shows Er FS?
You can continue using the refrigerator briefly, but it is not safe to leave it running unattended for an extended period with this code active. Without a functioning freezer sensor, the control board cannot regulate freezer temperature accurately, which puts frozen food at risk of thawing. Address the fault as soon as possible to avoid food spoilage.
How much does it cost to fix the Er FS error code on an LG refrigerator?
If the fix is simply reseating a loose connector, there is no parts cost at all. A replacement freezer thermistor for an LG refrigerator typically costs between $15 and $40 for the part. If a technician is needed, expect to pay a service call fee plus labor, usually totaling $100 to $200 depending on your area. A main control board replacement, if required, is significantly more expensive, often $150 to $300 for the part alone.
Is Er FS on my LG refrigerator a hard repair to do myself?
Checking and reseating the wiring harness is a low-difficulty task that requires only unplugging the unit and accessing the freezer interior. Testing the thermistor with a multimeter requires basic familiarity with the tool but is manageable for most DIYers with the correct resistance spec from the service manual. Replacing the thermistor itself is also a relatively accessible repair. If the control board is at fault, that replacement is more involved, and a technician is advisable if you are not comfortable with control board work.

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